In one aspect, this invention relates to controlling the rate of a cross-linking reaction that occurs during the curing of a chemical composition. In another aspect, this invention relates to an adhesive composition. In a further aspect, the invention relates to an adhesive composition that bonds to a chemically inert substance. In yet another aspect, this invention relates to bonding a chemically inert elastomeric tape to a substrate.
A wide variety of coatings for sumps, tank interiors, containment linings, flooring systems and joint overlays are known. However, such coatings tend to fail upon the failure or movement of the underlying substrate to which the coatings are bonded, generally by cracking, peeling or delaminating. The problem is worse where movement between adjacent substrates is likely, such as in a corner, or along an expansion joint or crack.
Coating integrity can be enhanced by adhering an elastomeric tape to the substrate along the just identified troubled areas. However, chemically inert elastomeric tapes, which are able to resist degradation by acids, bases and solvents, are very difficult to reliably bond to many substrates and require specialty adhesive. An adhesive which provides good bonding, has good flexibility and gap bridging properties between concrete, vinyl ester, epoxy and many other substrates would be very desirable.
An adhesive which retains these properties under conditions of low temperatures where many adhesive materials become brittle, or high temperatures where many adhesive materials loose strength, would also be very desirable.
Many adhesive systems are difficult to apply in the field. Extremes of field conditions, such as extremes of temperature or humidity, can make it further difficult to apply an adhesive so as to achieve a satisfactory bond. An adhesive which may be applied at a temperature as low as 5xc2x0 C., and as high as 60xc2x0 C., and over a wide range of humidity, without affecting its properties, would be very desirable. A chemically resistant adhesive is needed in various industrial applications. The majority of current adhesive systems are adversely affected by strong acids, bases and solvents and are also susceptible to degradation by ozone, UV-rays, and xcex3-rays. An adhesive system that is resistant to degradation by such agents, as well as to discoloration induced by these or other agents would also be very desirable.
In accordance with one embodiment of the invention there is provided a composition comprising a resin, and a curing agent. The composition can be used as an adhesive. In accordance with a preferred embodiment of the invention, the resin comprises a reactive polyolefin, at least one acrylate monomer, and an epoxy. The curing agent is a modified polyamine. An adhesive composition formed by mixing resin and curing agent is well adapted for adherence to a chemically inert elastomeric tape and substrates like concrete or coated concrete.
In an even more preferred embodiment, the reactive polyolefin component comprises a halogenated and chlorosulfonated polyethylene that is combined with sufficient acrylate monomer to achieve solubility. An alkyl phenol is added to prevent the resin from pre-gelling when in contact with the curing agent. The adhesive composition, obtained by mixing resin and curing agent, has good initial tack and cures over a time period ranging from a few minutes to a few hours. The cured composition has outstanding resistance to aggressive chemicals and outstanding adhesion to both concrete and to an elastomeric tape formed from related materials. Also, it has been found that incorporating a minor amount of trichloroethylene into the adhesive composition provides even further improved adhesion to the elastomeric tape.